Synthesis and magnetic properties of Co-Ti-Bi codoped M-type barium ferrite

Journal Article · Fri Apr 01 00:00:00 EDT 2011 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.3556772· OSTI ID:21560147

Lijun, Jia; Huaiwu, Zhang; Shuiming, Yin; Feiming, Bai; Baoyuan, Liu; Qiye, Wen; Jian, Shen ^[1]

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1. State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

The effects of Co{sup 2+}, Ti{sup 4+}, and Bi{sup 3+} substitution on the microstructures and properties of low-temperature fired M-type barium hexaferrites have been studied in order to adapt the development of low-temperature cofired ferrites technology and produce gyromagnetic devices with a multilayer process. It is found that Bi{sup 3+} ions can enter into the 2a sublattice and consequently enhance the grain growth and densification due to the activation of the lattice, which in turn first lead to an increase and then a decrease of M{sub s}. The substitution of Bi{sup 3+} ions is beneficial to forming the M phase and lowers the sintering temperature to about 900 deg. C, which is ideal for cofiring with silver paste. Scanning electron microscope and x-ray diffraction analysis have shown that the samples have excellent crystalline grains with a uniform size about 1-2 {mu}m. Moreover, nonmagnetic Ti{sup 4+} ions prefer to enter the 4f{sub VI} octahedral sites, giving rise to the weakening of the strong 12k-4f{sub VI} superexchange path and thus the isotropic exchange energy approaches the other second-order terms on the magnetic Hamiltonian, such as the antisymmetric interaction or even the magnetocrystalline anisotropy. With increasing the substitution content, some Co{sup 2+} ions, which locate in octahedral 12k sites, give a strong planar contribution to the anisotropy. Therefore, M{sub s} and H{sub c} decrease with the Co-Ti-substitution.

• OSTI ID: 21560147
• Journal Information: Journal of Applied Physics, Vol. 109, Issue 7; Conference: 55. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 14-18 Nov 2010; Other Information: DOI: 10.1063/1.3556772; (c) 2011 American Institute of Physics; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANISOTROPY
BARIUM COMPOUNDS
BISMUTH ADDITIONS
BISMUTH IONS
CERAMICS
COBALT ADDITIONS
COBALT IONS
COERCIVE FORCE
FERRITES
GRAIN GROWTH
GRAIN SIZE
INTERACTIONS
LAYERS
MAGNETIC PROPERTIES
SCANNING ELECTRON MICROSCOPY
SYNTHESIS
TITANIUM ADDITIONS
TITANIUM IONS
X-RAY DIFFRACTION
ALKALINE EARTH METAL COMPOUNDS
ALLOYS
BISMUTH ALLOYS
CHARGED PARTICLES
COBALT ALLOYS
COHERENT SCATTERING
DIFFRACTION
ELECTRON MICROSCOPY
FERRIMAGNETIC MATERIALS
IONS
IRON COMPOUNDS
MAGNETIC MATERIALS
MATERIALS
MICROSCOPY
MICROSTRUCTURE
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SCATTERING
SIZE
TITANIUM ALLOYS
TRANSITION ELEMENT ALLOYS
TRANSITION ELEMENT COMPOUNDS